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In response to widescale, voluntary uptake of escape gaps by commercial trappers using collapsible netted cylindrical (or "round") traps targeting blue swimmer crabs, Portunus armatus, in south‐eastern Australia, an observer‐based study was used to assess the adoption and effectiveness of the most common escape gaps across two estuaries responsible for >70% of all harvest. Five observers collected data from 5710 deployments of round traps over 116 days. Among 60% of round traps with escape gaps, 73% were rectangular shaped, and the rest were either circular or square. Catches were dominated by P. armatus (93%), but ~60% were undersized (<65‐mm carapace length; CL). Compared with round traps with no escape gaps, traps with a rectangular design consistently retained fewer undersized P. armatus (by up to 54%); similar to earlier, manipulative experiments. However, unlike previous observations, escape‐gap performance did not significantly improve with increasing catches of P. armatus. Eventual 100% adoption of escape gaps should enable large numbers of undersized P. armatus to escape traps and avoid discarding each year in south‐eastern Australia. [ABSTRACT FROM AUTHOR]

A distinctive frequency selective surface (FSS) to effectively enhance the electromagnetic shielding performance of high-speed electronic systems while preserving good mechanical ventilation is proposed in this article. The FSS consists of periodic segmented circular patterns in two-dimensional view and hollow vent holes in spatial, which exhibits a wide 2 GHz stopband at the interested frequency of 28 GHz. The new design also demonstrates stability to wave oblique incidence and polarization. The FSS shielding panel is prototyped and measured for validation. A satisfactory agreement between simulation and physical experiment is achieved. [ABSTRACT FROM AUTHOR]

A computer code is used to simulate the conditions that exist during a manhole event consisting of an electrical fault and a gas explosion. When energy is generated within the structure, pressures can reach levels sufficient to propel the cover from its frame. The code quantifies the effects of the event and provides guidelines for the design of safety devices that can minimize the potential danger of the event. Differences between chemically-driven and electrically-driven events are shown to require different design criteria for cover restraint systems. Devices designed to restrain the cover must be able to withstand explosive forces and react in sufficient time to reduce internally generated pressures. By understanding the fundamental characteristics of arcing faults and gas explosions and their effect on the internally generated pressures, safety devices can be designed to mitigate the effects of the event in manholes and vaults and thereby reduce the potential danger to maintenance crews, first responders and the public. [ABSTRACT FROM AUTHOR]

Increase in air temperature inside a parked car cabin causes negative impacts such as low thermal comfort, health risk for the passengers/pets inside the cabin, increased fuel consumption due to higher air-conditioning requirements. The present project focuses on methods to reduce the cabin temperatures for a car parked in unshaded condition. CFD analyses along with experimental validation have been performed with the use of different proposed cabin temperature control methods such as use of electrochromic tint on windshield, use of inlet and outlet vents, lowering of windows and combinations of these. Commercial CFD package ANSYS Fluent has been utilized to develop a numerical model for car cabin temperature distribution assessment when a parked car is subjected to solar load at different locations inside the cabin such as dashboard, seats and boot. A solar surface to surface radiation model is used in conjunction with solar calculator to capture the solar radiation that included change in position of the sun. A 5:1 scale down model of car cabin has been used for experimental validation with the help of help of PT-100 resistance thermometers. Good reduction in cabin temperatures has been observed for all the proposed cooling methods with 14 °C reduction for the combined tint, vents and lowered windows case. [ABSTRACT FROM AUTHOR]

Switching performance of a low-voltage switching device (LVSD) is determined by limiting current and stopping re-ignition. This is strongly influenced by how the arc moves inside the LVSD quenching chamber during the switching process. Improved switching performance is achieved when the arc quickly enters and stays inside the splitter plates of the LVSD, with the arc attached to the surface of the plates. This article studies arc motion around splitter plates in LVSDs and the correlation with arc voltage. Arc motion is investigated using a high-speed optical arc imaging system (AIS). It is observed that the arc fluctuates as it enters the splitter plates, with periods inside the plates followed by sudden re-strikes of the arc roots outside the plates. The AIS system allows the measurement of arc displacement and a correlation with the arc voltage. The results show two phases, with a narrow correlation while the arc in the chamber out of the splitter plates and a distributed correlation while in the splitter plates. Further, a new performance parameter the splitter time (ST) ratio is defined. The influence of the ST ratio on the chamber vent design is investigated. It is found that with wider and well-distributed vent apertures, the ST ratio is higher than with a closed vent, and arc motion on entry to the plates is improved. [ABSTRACT FROM AUTHOR]

Frequency response to stimuli applied to acoustic micro-electro-Mechanical Systems (MEMS) yield meaningful information of certain defects affecting such devices. This article presents the effects of three distinct root causes of failures affecting the low-frequency response of MEMS microphones: lid attach holes, die attach holes and broken vents with experimental inductions of these effects for the lid attach holes and broken vents. Methods to create such defects are presented which include laser drilling and focused ion beam machining of holes. A complete characterization of induced broken vents is presented. Alternative locations for defects induction are proposed and demonstrated on 34 devices, 16 with lid attach holes and 18 with induced broken vents. The information obtained from the frequency response of the devices is shown to be insufficient to separate the root causes of failures as their effects on the frequency response is similar and the magnitudes of the variations of the observed response overlap. Additional information about the circumstances regarding the onset of defects such as location of the fault and its occurrence in the device manufacturing/assembly/operation timeline is however sufficient for root cause identification. [ABSTRACT FROM AUTHOR]

Hydrothermal plumes are ongoing venting of hot solutions, on a time scale of months to years, relating to volcanic activities on the seafloor. Recent developments in acoustical observational techniques have produced images to support the scientific investigation of such plumes. However, understanding the complex behavior of plumes in a long-time series poses a challenge to the existing analysis approaches. The motivation of this work is to use visualization techniques to facilitate the visual exploration and analysis of plumes and to help domain scientists compare the actual behavior of plumes predicted by tidal interaction models and buoyant plume models incorporating forced entrainment effects. Methods of geovisualization are combined with time-varying feature-based techniques to create visualizations of plumes which are applied to an acoustic imaging dataset collected using the Cabled Observatory Vent Imaging Sonar in the Northeast Pacific. The results give new insights to the data and confirm the hypothesis of plumes. [ABSTRACT FROM AUTHOR]

This article deals with the stator cooling of an air-cooled, synchronous generator with a power rating of 400 kVA, which has been improved by adding two radial vents to the stator. To ensure an optimal vent design, a novel combined thermal and electromagnetic modelling approach is developed. A parametric 3D Conjugate Heat Transfer Computational Fluid Dynamics (CFD) model is used for the thermal modelling. An electromagnetic 2D Finite Element Analysis determined the impact that venting the stator has on the loss distribution. The models are coupled by deriving analytical correlations between the combined vent width and rotor copper, rotor iron and stator iron losses. These correlations are implemented into the optimisation procedure of the parametric CFD model. Five design parameters are optimised simultaneously with the aim of minimising the peak stator winding temperature. The modeling approach was validated experimentally by thermal, torque and mass flow measurements on the benchmark machine, as well as the newly designed prototype. [ABSTRACT FROM AUTHOR]

• 3D numerical DO radiation model simulation to evaluate the performance of SAH with perforated absorber plate having cross flow configuration. • The vent size and number of vents optimized for thermo-hydraulic performance. • Heat map of the thermohydraulic efficiencies for different collector configurations. Numerical analysis of a solar air heater with perforated circular absorber plate is carried out to study the effect on the thermo-hydraulic performance due to the elimination of laminar viscous layer that otherwise exist in a conventional solar air heater. The study is conducted for configurations of the absorber plate consisting of 5 mm, 8 mm, 10 mm and 12 mm vent diameters and the number of vents is varied as, 24, 36 and 54. The numerical CFD analysis is conducted for Reynolds numbers ranging from 3000 to 21,000. The CFD analysis is evaluated against the experimental results. The average increase in the thermal efficiency of 23.33% is obtained for the configuration with 8 mm diameter vents and 36 number of vents compared to the base model without the absorber plate. The average increase in thermohydraulic efficiency is 21.78% higher for the configuration with 36 vents and a vent diameter of 8 mm compared to the base model. The highest thermohydraulic efficiency of 72.8% is obtained. The thermohydraulic efficiency of the collector is directly proportional to the increase in vent diameter. The study infers that the circular geometry and vented absorber plate causes vortex formation resulting in increase in turbulence induced heat transfer. [ABSTRACT FROM AUTHOR]

There are many complicating factors that will determine the odour emissions from vents at sewage pump stations and on rising mains. One of the main factors is the formation of sulfide which is dependent on residence time of the sewage and the surface area to volume ratio of the wet well and rising main. A case study of sulfide formation modelling for a holding tank, rising main and vent located on the receiving gravity main is presented in this paper. ASK has developed software that calculates the concentration of sulfide formed within wet wells and rising mains based on Uniquest’s Sewex methodology of modelling the biochemical reactions with the rising main modelled as a plug flow system (Sharma et al, 2008). Initial concentrations and relevant parameters of the sewage, where unavailable, were assumed and tested to match the model predictions to measured values as closely as practicable. This approach takes into account the temporal and spatial variation of sulfide concentrations, in contrast to most models which assume a steady-state system. Another key factor of the release of odour is the rate at which hydrogen sulfide is released from the sewage, which is dependent on the concentration of sulfide in the liquid phase, the saturation concentration at equilibrium dependent on pH and temperature, and the turbulence of the system. When appropriate assumptions and initial conditions are set, the sulfide predictions match reasonably well with observations reported by Sharma et al (2008). [ABSTRACT FROM AUTHOR]

This paper provides a novel classification scheme for magma-induced subsurface vent complexes based on morphometric data and stacking patterns. The study area is the Naglfar Dome in the Vøring Basin where the interaction between magmatic intrusions and vent complexes is well known. Seismic interpretation, characterization and morphometric analyses of 35 vent complexes observed within the Palaeocene-Eocene strata were done from a high-quality, three-dimensional seismic reflection data. The vent complexes have dome-shaped, eye-shaped, fault-controlled and reactivated upper termini, and are linked to their root zones by columnar, downward-tapered and fault-related fluid conduits or pipes. Statistical analyses and cross plots of L-A and Dmax-Hmax allowed the discrimination of vents and pipes into their genetic types. A new classification scheme based on the morphometric sub-division and structures of subsurface vent complexes is introduced to include S-P-V, S-P-F, V-P-V and V-P-F types. These combinations freshly demonstrate the importance of morphometric data at deciphering the nature, timing, classification and activity of subsurface fluid vent complexes. [ABSTRACT FROM AUTHOR]

Subsurface pipes related to fluid flow are observed in seismic reflection data as vertical to sub-vertical features of low-amplitude reflections, linking chaotic reflections at the base (root zones) of volcanic constructs to their summits which can comprise craters, mounds or eye-shaped vents. To date, uncertainties remain regarding the linear correlation and scaling relationship between pipes and their overlying vent structures. Using 3D seismic reflection data from a magma-rich basin, the Vigrid Syncline in the Vøring Basin (offshore Norway), this study provides a seismic, morphometric and statistical description of forty (40) pipes and their associated structures. These pipes include conical, bifurcated, fault-controlled and columnar types, which are a consequence of the intrusion of two mappable magmatic sills of Early Eocene age. The heights (av. 1098 m), widths (av. 1740 m) and slenderness ratios (i.e. the heights/widths (Ω)) of the pipes (av. 0.6) show low to moderate correlation coefficients with vent parameters such as height (av. 258 m), area (av. 2.3 km2) and ellipticity (av. 1.5). The morpho-statistical analyses provided here show that 'pipe' formation mechanisms are mutually exclusive and that vent geometries are not particularly systematic in nature. [ABSTRACT FROM AUTHOR]

Molded underfill process provides many benefits for higher productivity and lower cost over the conventional capillary underfill process. However, the void defects in a molded underfill process could cause pop-corning effect and solder extrusion during the reflow process. This paper presents a highly efficient and accurate hybrid model that can be applied to diagnose the void risk in vacuum molded underfill processes of real flip-chip, package-on-package devices with complex ball arrays and large PCB strips. The model combines multi-zone porous media model, Hele-Shaw model and compressible two-phase computational fluid dynamics model. The model has been well validated in terms of the entrapped void size and its behavior with flow visualization experiments. Also, a set of parametric studies on a FC-POP molded underfill flow process were performed to pre-assess the future node’s molded underfill process. Not only the model provides a better understanding of the physics of void entrapment but also it is proven to be an effective tool for assessing the potential void risk through its application to 10nm flip-chip, package-on-package device manufactured in mass production line. [ABSTRACT FROM AUTHOR]

Polynoidae Kinberg, 1856 has five branchiate genera: Branchipolynoe Pettibone, 1984, Branchinotogluma Pettibone, 1985, Branchiplicatus Pettibone, 1985, Peinaleopolynoe Desbruyères & Laubier, 1988, and Thermopolynoe Miura, 1994, all native to deep-sea, chemosynthetic-based habitats. Of these, Peinaleopolynoe has two accepted species; Peinaleopolynoe sillardi Desbruyères & Laubier, 1988 (Atlantic Ocean) and Peinaleopolynoe santacatalina Pettibone, 1993 (East Pacific Ocean). The goal of this study was to assess the phylogenetic position of Peinaleopolynoe, utilizing DNA sequences from a broad sampling of deep-sea polynoids. Representatives from all five branchiate genera were included, several species of which were sampled from near the type localities; Branchinotogluma sandersi Pettibone, 1985 from the Galápagos Rift (E/V "Nautilus"); Peinaleopolynoe sillardi from organic remains in the Atlantic Ocean; Peinaleopolynoe santacatalina from a whalefall off southern California (R/V "Western Flyer") and Thermopolynoe branchiata Miura, 1994 from Lau Back-Arc Basin in the western Pacific (R/V "Melville"). Phylogenetic analyses were conducted using mitochondrial (COI, 16S rRNA, and CytB) and nuclear (18S rRNA, 28S rRNA, and H3) genes. The analyses revealed four new Peinaleopolynoe species from the Pacific Ocean that are formally described here: Peinaleopolynoe orphanae Hatch & Rouse, sp. nov., type locality Pescadero Basin in the Gulf of California, Mexico (R/V "Western Flyer"); Peinaleopolynoe elvisi Hatch & Rouse, sp. nov. and Peinaleopolynoe goffrediae Hatch & Rouse, sp. nov., both with a type locality in Monterey Canyon off California (R/V "Western Flyer") and Peinaleopolynoe mineoi Hatch & Rouse, sp. nov. from Costa Rica methane seeps (R/V "Falkor"). In addition to DNA sequence data, the monophyly of Peinaleopolynoe is supported by the presence of ventral papillae on segments 12-15. The results also demonstrated the paraphyly of Branchinotogluma and Lepidonotopodium Pettibone, 1983 and taxonomic revision of these genera is required. We apply the subfamily name Lepidonotopodinae Pettibone 1983, for the clade comprised of Branchipolynoe, Branchinotogluma, Bathykurila, Branchiplicatus, Lepidonotopodium, Levensteiniella Pettibone, 1985, Thermopolynoe, and Peinaleopolynoe. [ABSTRACT FROM AUTHOR]

The first definitive evidence for continental vents on Mars is the in situ detection of amorphous silicarich outcrops by the Mars Exploration Rover Spirit. These outcrops have been tentatively interpreted as the result of either acid sulfate leaching in fumarolic environments or direct precipitation from hot springs. Such environments represent prime targets for upcoming astrobiology missions but remain difficult to identify with certainty, especially from orbit. To contribute to the identification of fumaroles and hot spring deposits on Mars, we surveyed their characteristics at the analog site of the Solfatara volcanic crater in central Italy. Several techniques of mineral identification (VNIR spectroscopy, Raman spectroscopy, XRD) were used both in the field and in the laboratory on selected samples. The faulted crater walls showed evidence of acid leaching and alteration into the advanced argillic-alunitic facies, with colorful deposits containing alunite, jarosite, and/or hematite. Sublimates containing various Al and Fe hydroxyl-sulfates were observed around the active fumarole vents at 90 °C. One vent at 160 °C was characterized by different sublimates enriched in As and Hb sulfide species. Amorphous silica and alunite assemblages that are diagnostic of silicic alteration were also observed at the Fangaia mud pots inside the crater. A wide range of minerals was identified at the 665 m diameter Solfatara crater that is diagnostic of acid-steam heated alteration of a trachytic, porous bedrock. Importantly, this mineral diversity was captured at each site investigated with at least one of the techniques used, which lends confidence for the recognition of similar environments with the next-generation Mars rovers. [ABSTRACT FROM AUTHOR]

Pressure flow generally exists in water conservancy projects and pipelines. The flow boundary of the contraction section faces a potential risk of cavitation erosion under high velocity. However, there is a lack of effective methods to suppress cavitation in engineering practices with pressure flow, posing a challenge to the operational safety of discharge structures and pipeline devices. The purpose of this paper was to realize the application of air entrainment in a plug-type contraction section of pressure flow. It was found that a single air vent and a low air flow rate could achieve complete vena contracta aeration. The pressure profiles of the vena contracta were investigated, and the results showed that the pressure distribution allowed the entrained air to diffuse laterally and convectively. Finally, we proposed a fitting algorithm to predict the air concentration in the vena contracta. These conclusions are of great significance for improving the safety and cavitation resistance of the contraction section of pressure flow. [ABSTRACT FROM AUTHOR]

Lithium ion batteries have a well-documented tendency to fail energetically under various abuse conditions. These conditions frequently result in decomposition of the electrochemical components within the battery resulting in gas generation and increased internal pressure which can lead to an explosive case rupture. The 18650 format cell incorporates a vent mechanism located within a crimped cap to relieve pressure and mitigate the risk of case rupture. Cell venting, however, introduces additional safety concerns associated with the flow of flammable gases and liquid electrolyte into the environment. Experiments to quantify key parameters are performed to elucidate the external dynamics of battery venting. A first experiment measures the vent burst pressure. Burst vent caps are then tested with a second experimental fixture to measure vent opening area and discharge coefficient during choked-flow venting, which occurs during battery failure. Vent opening area and discharge coefficient are calculated from stagnation temperature, stagnation pressure, and static pressure measurements along with compressible-isentropic flow equations and conservation of mass. Commercially sourced vent caps are used with repeated tests run to quantify repeatability and variability. Validation experiments confirmed accuracy of opening area and discharge coefficient measurement. Further, trials conducted on vent caps from two sources demonstrate the potential for variation between manufacturers. [ABSTRACT FROM AUTHOR]

Abstract This work takes place in the context of potential hazards in the use of hydrogen in fuel cells. The present article describes comparisons between PIV measurements performed on a two vented cavity with an helium injection and Large Eddy Simulation of the same configuration. A two vented cavity is chosen because a quasi state is reached rapidly and it facilitates both CFD calculations by reducing the CPU costs and also enables statistical treatment of the data, the temporal averaging being possible at steady state. At the same time, this configuration is close to fuel cell designs, except for the set-up reduced size. We also describe the experimental set-up and the care which has to be taken to produce Particle Image Velocimetry velocity fields. The final goal of the paper is to validate a L.E.S approach as a good replacement to experiments, since access to both velocity and concentration fields is required to improve existing simplified models. Indeed, most of the 2 vents models rely on simplified assumptions such as a constant entrainment coefficient, a bi-layer formation which is not always the case in real situations. Highlights • L.E.S concentrations are conservative which is well suited for safety applications. • L.E.S results and experimental measurements exhibit strong similarities. • L.E.S and experimental results differences are mostly within a 20% range. • In the plume L.E.S fluctuations are much lower than in experiments. • DNS should be preferred to L.E.S calculations as a replacement for experiments. [ABSTRACT FROM AUTHOR]

Ocean hydrothermal activity is well known from deep-sea studies; however, few studies have been reported at shallow depth. A shallow submarine hydrothermal system at Punta Mita described in 2000 was studied to determine the grain size classification of the marine sediments of this hydrothermal system. Three sites with hydrothermal activity were included. Each one was divided into three areas: with hydrothermal activity, intermediate, and out of hydrothermal activity. In each area, two sediment cores were randomly collected by scuba diving (number of sediment cores = 18). All sediment samples were subjected to a previous treatment, to eliminate salts and organic matter. The grain sizes were sieved and then classified following the Udden–Wentworth scale. A principal coordinate analysis was performed to determine if there was any association of the statistical moments with the areas and sites of study. The textural composition of the sediments in the hydrothermal influence areas is sand, where the very fine sand is the dominant grain size, which was confirmed with the mean moment. The sediments are characteristic of the tidal areas, except for those sediments in the areas with hydrothermal activity.